In 2005, scientists discovered a few families in Hungary where some of the adults only walked on all fours. Few understood the causes of this rare condition, called Unertan syndrome. Some scientists speculated that the quadrupedal people had simply never learned to walk upright due to learning disabilities and lack of access to proper medical care. Others believed that these families had a mutation in a set of genes that cause humans to walk upright. Today at a conference, researchers in Turkey are presenting the results of a study where they analyzed the genomes in all four families. They are beginning to figure out what causes present-day humans to walk on all fours the way our distant ancestors did.